@misc{indiciae45057b4517e1,
  title = {Gamma-ray, magnetic, and topographic data for parts of the Colorado Front Range},
  author = {Joseph S. Duval and J. C. Reed and Isidore Zietz},
  year = {2001},
  doi = {10.3133/ofr00331},
  url = {https://pubs.usgs.gov/publication/ofr00331},
  note = {Source identifier: ofr00331}
}